Hi Folks, I've been seeing a boot hang/crash on power3 systems for a few weeks. (hangs on a 270, drops to SP on a p610). This afternoon I got around to tracking it down to the changes in
commit d9c2340052278d8eb2ffb16b0484f8f794def4de Do not depend on MAX_ORDER when grouping pages by mobility cpu 0x0: Vector: 100 (System Reset) at [c00000006e803ae0] pc: c00000000009bf50: .setup_per_zone_pages_min+0x298/0x34c lr: c00000000009be38: .setup_per_zone_pages_min+0x180/0x34c [c00000006e803e20] c0000000005e3898 .init_per_zone_pages_min+0x80/0xa0 [c00000006e803ea0] c0000000005c9c04 .kernel_init+0x214/0x3d8 [c00000006e803f90] c000000000026cac .kernel_thread+0x4c/0x68 I narrowed it down to the for loop within setup_zone_migrate_reserve(), called by setup_per_zone_pages_min(). The loop spins forever due to pageblock_nr_pages being 0. I imagine this would be properly fixed with something similar to the change for iSeries. Depending on how obvious, quick and easy it is for the experts to come up with a proper fix, I'll be able to do additional debug and hacking after turkey-day. :-) For the moment, I've hacked it with the following patch. (tested on both the 270 and the p610): --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2454,6 +2454,9 @@ static void setup_zone_migrate_reserve(struct zone *zone) reserve = roundup(zone->pages_min, pageblock_nr_pages) >> pageblock_order; +/* this is a cheap and dirty bailout, probally not a proper fix. */ + if (pageblock_nr_pages==0) return; + for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) { if (!pfn_valid(pfn)) continue; _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev